Punch



Patented July 31, 1928.

UNITED STATES PHILIPP SCHNEIDER, 0F ST. LOUIS, ,MISSOURI PUNCH.

Application filed February 21, 1927. Serial No. 169,904.

My invention relates to punches, and especially to that class of punches used' by sheet metal workers. I

The object of my invention is to provide a punch in which the bit, or point, can be removed readily and quickly, and renewed.

Other objects and advantages of my invention will be apparent from the specifica* tion, claim and drawings, in which Fig. l is a perspective view of my punch.

Fig. 2 is a like view, partly broken away andl in section.

Fig. 3 is a. p lan view of the detachable head.

vFig. 4 is a longitudinal. section of the detachable head, showing the punch point in place. i

Fig. 5 is a View of a punch ing the use of my punch.

IVhen punching a hole through sheet metal, in order that a. clean hole be punched and a portion of the metal cut away of a diameter equal to the diameter of the punch, it is necessary that the point of the punch have a plane, flat surface and that the periphery of the flat surface be substantially at right angles to the plane thereof, in orn der that the punch may eut a clean hole with a shearing effect. l

It is readily understood that the continued use of a metal punch, however well hardened, in punching holes through metal, the corners of the punch become worn and rounded, making it necessary to stop andl repress, y showf grind and repair the point. This causes unnecessary and expensive delay; and to avoid this objection I have devised a method by which a point when dull may be readily removed and a new one inserted at a minimum expenditure of time and labor.

My improved punch is preferably made of an outer cylindrical body 1 screw-threaded at its lower end 2 adapted to engage a like screw-threaded portion in the nut 3, which may be hexagonal, quadriangular, or other suitable shape that will permit the nut to be rotated by a wrench or othersuitable tool.

The nut 3 has its upper portion screwthreaded, as designated at 4, a sulicient distance from its upper end `to securely hold the body portion l when screwed into the nut.

The walls 5 of the lower portion of the y yThe bit holder nut 3 are sloped downwardly' and inwardly so as to leave a cone-shaped opening therein.

consists of a body 6, perforated through its longitudinal center adapted to lit closely a bit 7, which is inserted through the top end of body 6 of the bit holder, the bit being provided with a flanged head 8 to preventV its dropping through.

A plurality of longitudinal slots 9 are provided at the lower portion of the body1 6 of the bit holder adapted to be closed'together so as to clamp the bit when the body of the holder is forced downward by the cylindrical body l being screwed into the nut 3.

.A solid, cylindrical anvil l0` is inserted in the hollow cylindrical body l and proljects upwardly beyond the top of the cylindrical body l, l .firmly upon the top of the bit 7, thus when a blow is struck upon the top of the anvil 10, the force of the blow is imparted only to the bit 7.

It is quite obvious that I have greatly increased the efliciency of a sheet metal workers punch by being able to supply a number of detachable bits that can be readily and quickly attached to and detached from the punch anda new, sharp bit be inserted in lieu thereof.-

In Fig. 5 the use of my invention when applied to a hand-operated punch press is shown. It could, of course, be as readily adapted to power presses.

Having fully described my invention, what I claim as new and useful and desire to secure by Letters Patent is A punch of the class described, comprising a hollow frusto-conical-shaped bit holder having its lowerportion longitudinally slotted adapted to fit a conic opening in a nut, a screw-threaded, hollow, cylindrical portion adapted to be screwed into said nut thereby tending to force the said frustoconical bit holder outwardly, a solid cylindrical anvil ada-pted to reciprocate in said hollow, screwethreade'd, cylindrical portion when struck by a hammer thereby imparting energy to a bit enclosed in` said frustoconical bit holder, a bit having a flanged head, said bit being adapted to be rigidly held in said frusto-conical bit holder when saidy cylindrical' Vbody portion is screwed and its lower end presses into said nut, a nut having its uppei` portion hold 2L bit when Vsaid cylindrical portion is screw-throaded adapted to engage the sorowti glitly Screwod into said nut.

throadod portion of the said cylindrical porlfn Witness wlieioo' have hereunto aif- 10 tion, and an openingin its lower portion fixed my'signatuio 'this 6th day of January, having sloping Walls adapted to lit the pe- 1927.

riplieiy of the said fiusto-cone-slmped,

slotted bit holder and adapted to rigidly v PHILIPP SCHNEDER. 

